The present invention relates to equipment for the laser medical treatment of occlusions and lesions in arteries and other narrow regions within living organisms, with particular emphasis on the treatment of human patients. The present invention, while being especially suited for the treatment or removal of plaque and lesions from, for example, the coronary and femoral arteries, finds equal efficacy in many gynecological, urological and other internal procedures requiring narrow path access to the site of treatment.
More particularly, the present invention relates to a laser catheter and laser catheter/balloon angioplasty system for the delivery of laser energy and, more specifically, for the direct contact application of laser energy to the vascular or other site requiring treatment. Use of contact laser technology as a general surgical tool is described in applicant's issued U.S. Pat. Nos. B1 4,592,353; 4,693,244; and 4,736,743.
The treatment of partially or totally occluded arteries due, for example, to cholesterol-triggered plaque deposits has received substantial attention in recent years. Several systems have been proposed in this connection including "hot tips" (the laser or other heating of a metal tip); exposed indirect laser irradiation; and non-directed contact laser treatment. Each of these approaches, however, has failed to fully address one or more of the intrinsic problems associated with narrow path "recanalization" (i.e. the opening of arteries or other narrow channels through the removal of lesions and occlusions). These problems include, for example, the mechanical or thermal perforation of arterial walls; the generation of embolisms due to particles or gas bubbles; and the thermally induced shrinkage of associated walls. The present invention provides an efficacious treatment capability while substantially lowering these adverse risks.